(a) Field of the Invention
The present invention relates to an improved structure of a pencil sharpener, and in particular, to a pencil sharpener which has pencil sharpening function and has new function of light emitting and music producing.
(b) Description of the Prior Art
ROC patent publication no. 187347 entitled "A Pencil Sharpener With Music And Light Indiction Effect" discloses a pencil sharpener comprising a main body having an aperture for the insertion of a pencil, one lateral edge of the aperture being provided with a blade and being connected to an IC musical disc, a buzzer and a light bulb, and the other lateral edge of the aperture being located near to the center of the pencil tip, a conductive spring disc being connected to the IC musical disc, and the light bulb.
After a pencil has been sharpened, the tip of the pencil causes the blade and the conductive spring disc to electrically connect to a power source, which forms a closed circuit to produce a sound and light effect to indicate that the pencil has already been sharpened.
The conventional pencil sharpener structure employs the pencil tip to simultaneously touch the blade and the conductive spring to produce a closed circuit so that electrical current will pass through the pencil tip from the blade to the conductive blade. However, the following drawbacks are found in this conventional art;
1) Friction is formed when the conductive spring and the pencil tip are in contact. The pencil tip will be scratched and the conductive spring will be worn out after a long period of use. PA1 2) Although the pencil tip is conductive, its conductivity is not as good as metallic materials. In other words, the conductivity of the pencil tip is poor. PA1 3) Music is only played after the pencil has been sharpened, therefore, the process of sharpening is dull without music.